We describe two all-fiber devices for converting light from the fundamental mode to the second-order set of modes in optical fibers. The first is made by controlled hole collapse in a photonic crystal fiber, and the second is a twisted fused coupler made from few-moded conventional fiber. As well as having applications within fiber optics, the devices can be used to generate azimuthally polarized free-space beams.
© 2008 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: November 8, 2007
Revised Manuscript: January 9, 2008
Manuscript Accepted: January 12, 2008
Published: February 6, 2008
A. Witkowska, S. G. Leon-Saval, A. Pham, and T. A. Birks, "All-fiber LP11 mode convertors," Opt. Lett. 33, 306-308 (2008)